Circuit interrupter



1949. a. P. BAKER ETAL 2,477,781

CIRCUIT INTERRUPTER Filed Oct. 7, 1946 a sheds-sheet 1 WITNESSES:

INVENTORS z fienjamtn Pfia/rer and am es /I, (z/ m my M Aug. 2, 1949.

B. P. BAKER ETAL CIRCUIT INTERRUPTER s Sheets-Sh aet 2 Filed 001;. 7,1946 INVENTORS fienjamin P5 and James /7. ('umm ny- WITNESSES: 1

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Aug. 2, 1949. B. P. BAKER ETAL 7 CIRCUIT INTERRUPT Filed Oct. 7, 1946 3Sheets-Sheet 3 WITNESSES: INVENTdRS fiery am 1'27 Ffia/Fer a James /7.Cumming? 704M BY 4 ATTORNE Patented Aug. 2; 1949 UNITED STATES PATENTOFFICE CIRCUIT INTERRUPTER Benjamin P. Baker and James M. Cumming,Turtle Creek, Pa., assignors to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application October 7,1946, Serial No. 701,846

9 Claims. (01. 200-150) This invention relates to circuit interrupters,in general, and, more particularly, to arc-extinguishing structurestherefor.

Circuit interrupters of the prior art employed to interrupt high voltagecircuits have employed a number of serially related breaks to minimizethe voltage to be interrupted at each break. However, the prior artcircuit interru'pters involving a number of breaks have beencomplicated, costly to manufacture because of their complexity andwasteful of longitudinal space.

The principal object of our invention is to pro vide a simplified,compact circuit interrupter hav-- ing a considerable number of seriallyrelated breaks especially adaptable for the interruption of high voltagecircuits such as a 287 k. v. circuit in three or less cycles, and toarrange the breaks in an advantageous manner to minimize longitudinalspace. However, certain features of our invention are also adaptable forthe interruption of low voltage circuits.

Another object of our invention is to provide an improved circuitinterrupter in which the arcextinguishing units are of improvedconstruction and also in which the contact means may be readilyinspected and replaced if necessary.

Another object is to provide an improved circuit interrupter in whichthe several parts thereof are of simplified construction and may bereadily repeated for high voltage application.

Another object is to provide an improved circuit interrupter of verycompact construction comprising a plurality of serially relatedsuperimposed arc-extinguishing units in which the contact separation iseffected in a simplified and positive manner.

Another object is to provide an improved circuit interrupter involvingone or more arc-extinguishing units in which a pressure-generating arcis established within a substantially annular pressure-generating arcpassage and is utilized to direct fluid toward an interrupting are whichis established within a segmental portion of an annular ventedinterrupting passage.

Still another object is to provide an improved piston construction for acircuit interrupter of the high voltage type to facilitate low currentinterruption.

Further objects and advantages will readily become apparent upon areading of the following specification taken in conjunction with thedrawings, in which:

Figure 1 is a. side elevational' view, partly in section, of a circuitinterrupter embodying our 2 invention and shown in the closed circuitposition;

Fig. 2 is an enlarged vertical sectional view through the right-handarc-extinguishing assemblage of the interrupter of Fig. 1, the contactstructure being shown in the closed circuit position;

Fig. 3 is an enlarged vertical sectional view through our improvedarc-extinguishing unit, taken along the line III-'III of Fig. 6, thecontacts being shown in the closed circuit position;

Fig. 4 is an enlarged sectional view taken along the line IVIV of Fig.2;

Fig. 5 is a sectional view taken along the line VV of Fig. 3;

Fig. 6 is a sectional view taken along the line VI-VI of Fig. 3;

Fig. 7 is a sectional view taken along the line VII-VII of Fig. 3;

Fig. 8 is a sectional view taken along the line VIII-VIII of Fig. 3; and

Fig. 9 is a perspective view of our improved relatively stationarybridging contact construction showing how it may be easily removed fromand inserted into the arc-extinguishing assemblage.

Referring to the drawings, and more particularly to Fig. 1, thereference numeral I designates a tank filled to the level 2 with asuitable arcextinguishing fluid 3, in this instance circuit breaker oil.Depending from the cover 4 of the tank I are two insulating terminalbushings designated by the reference numerals 5, 6 to the lower ends ofwhich are secured identical arcextinguishing assemblages, generallydesignated by the reference numeral 1. A conducting bridging member 8electrically interconnects. the two arc-extinguishing assemblages l inthe closed circuit position of the interrupter .as shown in Fig. 1. Aninsulating actuatingrod 9 is employed for effecting verticalreciprocating motion of the bridging member 8. Suitable mechanism (notshown) is utilized for effecting motion of the actuating rod 9.

Referring to Fig. 2 which shows in more detail our improvedarc-extinguishing assemblage 1, it will be observed that the assemblage1 includes a plurality of arc-extinguishing units generally designatedby the reference numeral I0 and disposed in serially relatedsuperimposed abutting relationship. The units H] are mounted in stackedrelation to each other upon a casting member 34, a circular insulatingplate member 14 being disposed therebetween. Insulating .tie

rods ll may be employed for maintaining the several arc-extinguishingunits l rigidly in position. The upper ends of the insulating tie rodsii are enlarged and fixed to a metallic plate l2, the latter beingsecured by bolts l3 to a top casting M. The upper portion of the castingl4 forms a piston means including a piston chamber I5 in whichreciprocally moves a piston member 1 6, the latter being spring-biaseddownwardly by a compression spring H. The piston means including thepiston member i 6 operable in the piston chamber i5 is charged againstthe downward biasing action exerted by the compression spring H by theupward movement of a movable contact carriage generally designated bythe reference numeral i8 and including a Pair of parallel operatingrods, generally designated by the reference numerals l8 and 28.

The operating rods i9, are secured together at their lower ends by across-head 2| of conducting material having a recess 22 formed therein,

which recess is in abutting relation with the upper end of a movabledisconnect contact 23. The disconnect contact 23 is secured at theextremity of the conducting bridging member 8, as more clearly shown inFigs. 1 and 2. Upward movement of the movable disconnect contact 23causes upward movement of the contact carriage 118 against the downwardbiasing action exerted by the accelerating springs 24 disposed at thelower end of the assemblage l.

The construction of the operating rods i9, 20 is such as to provide azig-zag current path through the assemblage 7, as shown more clearly inFig. 2. More specifically, each operating rod 59, 20 has alternatelydisposed conducting portions 25 and insulating portions 26. Theseportions 25, 2B are supported by elongated insulating operating rods 21,which extend upwardly through both operating rods I9, 20. The insulatingportion 28 includes an insulating sleeve 28 surrounding the insulatingoperating rod 21. Ihe conducting portion 25 includes an interiorlypositioned conducting sleeve 29 immediately surrounding the insulatingoperating rod 2?. However, the conducting sleeve 29 is in turnsurrounded by an insulating sleeve 30. Disposed between the insulatingsleeves 28 and 30 is a ringshaped movable contact 3| which makesengagement with relatively stationary bridging contact means 32 disposedat the upper end of each unit ill.

Fig. 9 shows more clearly the construction of the relatively stationarybridging contact means 32. It will be observed that an elongatedconducting bar 33 is provided having a central portion 35 removedtherefrom. Disposed within the cutout portion 35 are a pair of opposedrelatively stationary contact segments 36, more clearly shown in Fig. 5.Each of the contact segments 36, is biased inwardly by a compressionspring 3'! disposed between the wall of the cutout portion 35 and theinner end of a recess 38 provided in each stationary contact segment 36as shown in Fig. 5.

It will be observed that the bridging contact means 32 may be easilyremoved from the assemblage I by lateral movement thereof upon thedownward removal of the two operating rods i9, 20. This method ofholding the contact structures 32 in position is more clearly shown inFig. 5. After the relatively stationary bridging contacts 32 have beenplaced into position between the opposed insulating plates 39 (Fig. 5),the upward movement of the operating rods 19, 20 into the ends of thecutout portion 35 of the Contact structure 32 securely holds the contactstructure 32 in position while at the same time permitting the mountingto be sufficiently flexible to accommodate any variations present on therods II, 20.

In the closed circuit position of the interrupter shown in Figs. 1-3,the electrical circuit therethrough includes the terminal stud (notshown) passing interiorly through the terminal bushing 6, top castingl4, slider contact fingers 40 (Fig. 2) supported by the casting l4,conducting sleeve 4!, ring-shaped movable contact 3i, relativelystationary bridging contact 32, upper right-hand movable ring-shapedcontact 3! associated with the right operating rod l5, conducting sleeve29, ring-shaped contact 3!, to the left through relatively stationarybridging contact 32 and so forth, in a zig-zag manner to the lower endof the assemblage l. The current path extends from the lowermostbridging contact 32 through the lower ring-shaped movable contact 3|associated with the left-hand operating rod 20, through the conductingsleeve 42 to the conducting cross-head 2|, from whence the circuitpasses through the movable disconnect contact 23 to the conductingcross-member 8. The circuit passes through the left-handarc-extinguishing assemblage 1 (Fig. l) in an identical manner to theterminal stud passing through the left-hand terminal bushing 5 of theinterrupter.

During the opening operation, suitable means (not shown) but which maybe responsive either to manual operation or to excessive current passingthrough the interrupter, causes downward motion of the lift rod 9. Thedownward movement of the lift rod 9 causes corresponding downwardmovement of the conducting cross-member 8 and hence downward movement ofthe two movable disconnect contacts 23 secured to the opposedextremities of the conducting cross-bar 8.

Considering only the right-hand arc-extinguishing assemblage I,referring to Fig. 2, it will be apparent that the acceleratingcompression springs 24 initially cause downward following movement ofthe movable contact carriage IS in response to lowering of the movabledisconnect contact 23. The downward motion of the movable contactcarriage l8 causes corresponding downward motion of the two operatingrods IS, 20 to simultaneously establish a pair of serially related arcsin each arc-extinguishing unit HI, the construction of which will bedescribed hereinafter. It will be observed that the downward motion ofthe operating rods 19, 20 permits the compression springs H to causedownward motion of the piston I6 within the piston chamber l5, ii thecurrent being interrupted is not too high. Circuit interruption soonoccurs and the conducting cross-head 2| in striking a dash pct 43disposed at the lower end of the assemblage l permits separation to takeplace between the recess or relatively stationary disconnect contact 22and the upper tip of the movable disconnect contact 23.

The dash pct 43 comprises a movable piston 44 having apertures 45provided therein which are closed off by an upstanding cylindricalportion 43 of a lower ring plate 4'! threadedly secured at 48 to thelower end of a ring-shaped conducting casting 49. Preferably, the piston44 is biased upwardly by a compression spring 50 seated upon a lower cap5| secured by bolts 52 to the lower ring plate 41.

The dash pct 43 is effective to cushion the stopping of the downwardmovable contact'carriage H} at the end of its opening movement. Asmentioned previously, the circuit has been interrupted when theconducting cross-head 2i strikes the dash pct 49 to be arrested thereby,thus permitting the movable disconnect contact 29 to separate from therecess or contact 22 to insert an isolating gap into the circuit, asmore clearly shown by the dotted lines in Fig. 1.

The internal construction of the arc-extinguishing units In will now bedescribed. Referring to Fig. 3, which shows enlarged a verticalsectional view through the arc-extinguishing unit i0 taken on the lineIII-DI of Fig. 6, it will be observed that the unit in is formed by theuse of a plurality of suitably configured insulating plates disposed insuperimposed contiguous relationship and held in place by the insulatingtie rods Ii. The top flow plate 53 of the unit I. has a configurationmore clearly shownin Fig. 7. It will be observed that the insulating nowplate 59 has two apertures 54 provided therein together with a centrallydisposed cutout portion 55. On the same level as the plate 53 is acentrally disposed round plate 55 having a lower projection 51 which isemployed to hold it in position.

It will be observed that the flow plate 59 permits a flow .of fluid totake place between the pressure-generating are (not shown) which isdrawn within a substantially annular pressuregenerating arc passage,generally designated by the reference numeral 58 and the interruptingare (not shown) which is established within a segmental portion of anannular interrupting arc passage, generally designated by the referencenumeral 59 in Fig. 3.

Immediately below the insulating flow plate 53 is an insulatingpartition plate 55, more clearly shown in Fig. 6. The partition plate 50has the apertures 54 provided therein and also has an aperture 6| formedtherein closely confining the insulating operating rod l9. It will beobserved that there is some clearance provided between the aperture GIand the operating rod l9 to permit a flow of liquid to take place pastthe partition plate 69. The partition plate 50 also has an aperture 62formed therein to closely confine the operating rod 28. The aperture 92has a notch 63 formed therein, the purpose for which will appear moreclearly hereinafter.

Immediately below the insulating partition plate 80 is an insulatingvent plate 54, the configuration of which is more clearly shown in Fig.6. The insulating vent plate 64 has apertures 54 provided therein whichcommunicate with a pair of intersecting inlet passages 65, the latterleading toward the substantially annular pressuregenerating arc passage58 to form a pool of liquid 15 therealong. Also the vent plate 54 has avent passage 66 formed therein to permit venting of the substantiallyannular interrupting passage 59 to the region exterior of the unit It.

Immediately adjacent to the vent plate 54 is a second insulatingpartition plate 58 having a construction identical to the partitionplate 55 previously described. Below the second insulating partitionplate 60 is a second flow insulating plate 53 having a configuration thesame as previously described and shown more clearly in Fig. 7. Below thesecond insulating flow plate 53 is a barrier insulating plate 81, theconfiguration of which is more clearly shown in Fig. 7. The barrierinsulating plate 61 has apertures 54 provided therein and also apertures58, which closely confine the insulating sleeves 28, 88 of operatingrods i9, 20, respectively. Below the barrier insulating plate 61 is apocket insulating plate 55,

which also has apertures 54 provided therein. The configuration of thepocket insulating plate 59 is more clearly shown in Fig. .8.

It will be observed that the insulating plate 59 has annular recessesIll provided therein which prevent loss of fluid pressure downwardlyalong the side walls of the annular arcing passages 59, 59. Below theplate 89 is a second barrier insulating plate 81 which is in turnfollowed by a second pocket insulating plate 59. most plat in the unitI! is a barrier insulating plate 81 which has a configuration aspreviously described.

It will be apparent that upon alignment of the several plates there willbe provided passage means including two vertically extending passages,generally designated by the reference numeral ll, interconnecting thepiston chamber 15 with the several units ID.

During the opening operation, assuming the current conditions to behigh, it will be apparent that two arcs (not shown) are drawn in eachunit H) in the substantially annular restricted pressure-generating arcpassage 59 and in the restricted segmental portion of the annularinterrupting arc passage, 59 as defined by the notches 69. Since theunits In are immersed in oil, there is a readily available quantity ofoil disposed adjacent the arcs within the recesses provided by theseveral plates and especially in the liquid pools I5. Referring to Fig.3, it will be apparent that the pressure are drawn in the pressurepassage 58 will react upon the oil disposed therealong and especially inthe pool 15 to force liquid to flow through the connecting passages(Fig. '7) in the two flow plates 59 toward the interrupting arc which isdrawn within the interrupting passage 59 as defined .by the notches 69.The notches 69 provided in the two partition plates 60 force theinterrupting arc to be drawn therein, thereby preventing theinterrupting are from being displaced around the surface of theinsulating sleeve 30 adjacent the open side of the vent passage 66. Theoil which passes through the connecting passages 12 provided in the flowplates 59 must pass upwardly and downwardly through the two notches 93adjacent to the interrupting are before it is vented out of the unit I.by means of the vent passage 65.

It will be apparent that by providing substantially annular arc passages58, 59 with the operating rod members I9, 20 substantially filling saidare passages, a desirable restricting of the two serially related arcsis provided in each unit 19. During the interruption of high currents,the pressure generated adjacent the pressure arc will act backwardlythrough the inlet passages 55 and upwardly through the vertical flowpassages H to prevent downward movement of the piston l5 within thepiston chamber l5. In other words, during the interruption of highcurrent, the back pressure is too great to permit operation of thepiston means. It is only during the interruption of relatively low powerthat the pressure is sumciently low to permit the compression spring I!to force the piston l5 downwardly within the piston chamber l5 to forceoil downwardly through the vertical flow passages II and into the inletpassages 55 provided in each unit I 0 by the insulating vent plate 54.Thus, the pressure are in each unit I8 is acted upon by oil driven fromthe piston means through the inlet passages 65. This oil flow increasesthe pressure generated at the pressure-generating arc and also tends toeflect the extinction of the The lowersame. As previously mentioned, theresulting oil flow from the pressure arc passes through the connectingpassages i2 provided in the two plates $3 of each unit it) toward theinterrupting are drawn within the interrupting passage 59. The oil inpassing through the notches 63 comes into intimate engagement with theinterrupting arc to pass out of the unit In through the vent passage 56.

By the time the operating rods 19, 20 and the cross-head 2i strike thedash-pot 43, arc extinction has already transpired, and the tip of themovable disconnect contact 23 is forceably withdrawn from the stationarydisconnect contact 22 provided in the conducting cross-head 5!. Certainfeatures of the disconnect arrangement are more fully set forth andclaimed in United States patent application, Serial No. 696,571, filedSeptember 12, 1946, now U. S. Patent 2,460,450, issued Februar 1, 1949,to James M. Cumming, and assigned to the assignee of the instantapplication. Also certain features of the interrupting structure hereinset forth are illustrated and claimed in United States patentapplication, Serial No. 465,244, filed November 11, 1942, now U. S.Patent 2,406,469, issued August 27, 1946, by Leon R. Ludwig, Winthrop M.Leeds and Benjamin P. Baker, and assigned to the assignee of the instantapplication.

It will be observed that certain features of the pressure-generating arcpassage 58 are similar to those of the interrupting structure set forthand claimed in United States Patent 2,253,009, issued August 19, 1941,to Benjamin P. Baker, entitled Circuit interrupter" and assigned to theassignee of the instant application.

From the foregoing description, it will be apparent that we haveprovided an improved circuit interrupter of the type drawing pressureand interrupting arcs in which more effective interrupting conditionsare brought to bear upon both the pressure are and the interrupting arcin each extinguishing unit ill. By the provision of the operating rodsi9, 20 having sleeve portions 28, 30 therealong which closely confinethe two serially related arcs, effective interrupting conditions arebrought to bear upon both arcs. During the interruption of low power,the piston means is operative to send fluid through the inlet passages65 toward the pressure arc to increase the pressure thereabout and totend to effect the extinction of the same.

The construction is simplified inasmuch as by withdrawal of the twooperating rods I9, 20 downwardly out of the assemblage 1, the relativelystationary contact structures 32 may be laterally removed from theassemblage '1 between the insulating plates 39. Upon their replacement,they are merely held in position by the presence of the rods I9, 28which may be moved upwardly into the several cutout portions 35 providedin the several relatively stationary contact structure" 32. In the fullyopen circuit position, shown by the dotted lines 73 of Fig. 1, twoisolating gaps are provided in the circuit and fresh oil within the tankI is permitted to enter the several units In through the vent passages66.

Although we have shown and described a specific structure, it is to beclearly understood that the same was merely for the purpose ofillustration and that changes and modifications may readily be madetherein by those skilled in the art without departing from the spiritand scope of the appended claims.

We claim as our invention:

1. In a circuit interrupter, an arc-extinguishing assemblage including aplurality of arc-extinguishing units each having two openingstherethrough, contact means associated with each arcextinguishing unit,a pair of axially movable spaced operating rods each extending throughone of the openings in each unit of the assemblage, and each operatingrod having alternately disposed conducting portions and insulatingportions, said conducting portions being covered with insulation exceptat the end portions thereof which coact with the several contact meansso as to provide a zig-zag current path through the assemblage.

2. In a circuit interrupter, means defining at least a pair ofarc-extinguishing units disposed in abutting relationship, each of saidarc-extinguishing units having two openings therein, relativelystationary bridging contact means disposed at one end of each unit, apair of axially movable spaced operating rods extendin within the twoopenings in the units, each operating rod having alternately disposed aconducting portion and an insulating portion, each of said conductingportions being covered with insulation except at the end portionsthereof which coact with the several bridging contact means, and saidconducting portions and bridging contact means providing a zig-zagcurrent path through the units in the closed circuit position of theinterrupter.

3. In a circuit interrupter, means defining at least a pair ofarc-extinguishing units disposed in abutting relationship. each of saidarc-extinguishing units having two openings therein, relativelystationary bridging Contact means disposed at one end of each unit, apair of axially movable spaced operating rods extending within the twoopenings in the units, each operating rod having alternately disposed aconducting portion and an insulating portion, each of said conductingportions being covered with insulation except at the end portionsthereof which coact with the several bridging contact means and saidconductin portions and bridging contact means providing a zig-zagcurrent path through the units in the closed circuit position of theinterrupter, and each relatively stationary bridging contact means beinglaterally removable from it unit following withdrawal of the twooperating rods. from the units.

4. In a circuit interrupter, an arc-extinguishing assemblage including aplurality of arc-extinguishing units having two parallel openingstherein, a, pair of axially movable spaced operating rods extendinwithin the said two parallel openings, each operating rod having atleast a conducting portion and an insulating portion, relativelystationary bridging contact means associated with each unit, and theconducting portion of one operating rod being opposite to the insulatingportion of the other operating rod and coacting with the bridgingcontact means so as the provide a zig-zag current path through theassemblage in the closed circuit position thereof.

5. In a circuit interrupter, an arc-extinguishing assemblage includinga, plurality of serially related arc-extinguishing units having twoparallel openings therein, an axially movable contact carriage includinga pair of axially movable parallel disposed operating rods each in oneof said openings, each operating rod having a conducting portion and aninsulating portion disposed in end-to-end relationship, relativelystationary bridging contact means associated with each unit, theconductin portions of the operating rods being alternately disposed andcooperating with the stationary bridging contact means to establish azig-zag current path through the assemblage, and disconnect meansseparable from the contact carriage for actuating the movable contactcarriage, the disconnect means separating from the contact carriage inthe fully open cirerating arc passage and a substantially annularinterrupting passage within the unit, the pair of parallel operatingrods being movable along the arc passages, each rod having a movablecontact secured to and movable therewith, the pair of movable contactsmakin engagement with the bridging contact in the closed circuitposition of the interrupter, a vent plate configured to permit ventingof the interrupting arc passage and to provide a pool of liquid alongthe Walls of the pressure are passage adjacent to the pressuregeneratingarc, and a pair of partition plates on opposite sides of the vent platehaving apertures therein closely confining the two operating rods.

7. In a circuit interrupter, an arc-extinguishing unit immersed in anarc-extinguishing liquid, a relatively stationary bridging contactdisposed at one end of the unit, suitably configured insulating platestructure including a pair of parallel operating rods for defining asubstantially annular pressure-generating arc passage and asubstantially annular interrupting passage within the unit, the pair ofparallel operating rods movable along the arc passages, each'rod havinga movable contact secured to and movable there- 'with, the pair ofmovable contacts making engagement with the bridging contact in theclosed circuit position of the interrupter, a vent plate configured topermit venting of the interrupting arc passage and to provide a pool ofliquid along the walls of the pressure are passage adjacent to thepressure-generating arc, a pair of partition plates on opposite sides ofthe vent plate'having apertures therein closely confining the twooperating rods, and a flow plate on the opposite side of each partitionplate providing communication between the two are passages.

lating plate structure including a pair of axially movable paralleloperating rods for defining a substantially annular pressure-generatingarc passage and a substantially annular interrupting passage within theunit, the pair of parallel operating rods movable along the arcpassages, each rod having a movable contact secured to and movabletherewith, the pair of movable contacts making engagement with thebridging contact in the closed circuit position of the interrupter, avent plate configured to permit venting of the interrupting arc passageand to provide a pool of liquid along the walls of the pressure arcpassage adjacent to the pressure-generating arc, a pair of partitionplates ,on opposite sides of the vent plate having apertures thereinclosely confining the two operating rods, 9, fiow plate on the oppositeside of each partition plate providing communication between the two arcpassages, and the two partition plates having notches provided thereinto position the interrupting are on the opposite side of the operatingrod from the vent passage in a segmental restricted portion of the arcpassage.

9. In a circuit interrupter, an arc-extinguishing unit, a bridgingcontact disposed at one end 01 the unit including a conducting barhaving a cut-out portion, a pair of opposed contact segments positionedwithin the cut-out portion, and a pair of operating rods carryin a pairof movable contacts movable through the ends of the cut-out portion.

BENJAMIN P. BAKER. JAMES M. CUMMING.

REFERENCES crrnn The following referenices are of record in the file ofthis patent:

UNITED STATES PATENTS

